My guess would be the advanced DNS. Did you recently change your IP or something with your DNS record? I did a quick search and found it looks like it has probligated over to Dlink's OpenDNS wanna be 204.194.232.200 at 65.18.174.63. Also, do you host your site on your PC your trying to access it from? That brings some routing questions to mind to. For now try turn it off at:
Basic > Manual Configure > Uncheck "Enable Advanced DNS Service"
If that doesn't work, ping and trace with and without router, by both IP and domain, see where the issue is.